Abstract:
By using a set of self-invented clamps and thin-walled tubular specimens with small diameter, a series of monotonic tension tests at different temperatures and low cycle fatigue tests at 375 ℃ for Zr-4 and Zr-1Nb alloys were carried out, then monotonic and cyclic constitutive relationships and Manson-Coffin life-estimating expressions for two alloys were given. The results show that the Young’s modulus, yield stress, tensile strength, and strain hardening decrease significantly with increasing temperature, however, the higher temperature is, the less effect of temperature on the strain hardening for Zr-4 is. The uniaxial properties of Zr-4 were hardly affected by the strain rate at 375 ℃. Under constant strain amplitude cycling, Zr-4 presents cyclic hardening especially at lower strain amplitude. Zr-1Nb shows cyclic hardening at lower strain amplitude, however it exhibits cyclic soften at higher strain amplitude. Comparing to the monotonic tension behavior, Zr-4 presents cyclic strain hardening evidently at different temperatures.